litmus-rt.git - The LITMUS^RT kernel.

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author	Ananth N Mavinakayanahalli <ananth@in.ibm.com>	2005-11-07 04:00:07 -0500
committer	Linus Torvalds <torvalds@g5.osdl.org>	2005-11-07 10:53:45 -0500
commit	66ff2d0691e00e1e7bfdf398a970310c9a0fe671 (patch)
tree	f53bcd846be8fbaee5a5ee65f9bacc5b34392090 /arch/x86_64/kernel/kprobes.c
parent	b385676b355549afc9a7507ce09c7df47f166521 (diff)

[PATCH] Kprobes: rearrange preempt_disable/enable() calls

The following set of patches are aimed at improving kprobes scalability. We currently serialize kprobe registration, unregistration and handler execution using a single spinlock - kprobe_lock. With these changes, kprobe handlers can run without any locks held. It also allows for simultaneous kprobe handler executions on different processors as we now track kprobe execution on a per processor basis. It is now necessary that the handlers be re-entrant since handlers can run concurrently on multiple processors. All changes have been tested on i386, ia64, ppc64 and x86_64, while sparc64 has been compile tested only. The patches can be viewed as 3 logical chunks: patch 1: Reorder preempt_(dis/en)able calls patches 2-7: Introduce per_cpu data areas to track kprobe execution patches 8-9: Use RCU to synchronize kprobe (un)registration and handler execution. Thanks to Maneesh Soni, James Keniston and Anil Keshavamurthy for their review and suggestions. Thanks again to Anil, Hien Nguyen and Kevin Stafford for testing the patches. This patch: Reorder preempt_disable/enable() calls in arch kprobes files in preparation to introduce locking changes. No functional changes introduced by this patch. Signed-off-by: Ananth N Mavinakayahanalli <ananth@in.ibm.com> Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Diffstat (limited to 'arch/x86_64/kernel/kprobes.c')

-rw-r--r--

arch/x86_64/kernel/kprobes.c

1 files changed, 14 insertions, 14 deletions

         int ret = 0;
         kprobe_opcode_t *addr = (kprobe_opcode_t *)(regs->rip - sizeof(kprobe_opcode_t));
-        /* We're in an interrupt, but this is clear and BUG()-safe. */
-        preempt_disable();
         /* Check we're not actually recursing */
         if (kprobe_running()) {
                 /* We *are* holding lock here, so this is safe.
                 goto no_kprobe;
         }
+        /*
+         * This preempt_disable() matches the preempt_enable_no_resched()
+         * in post_kprobe_handler()
+         */
+        preempt_disable();
         kprobe_status = KPROBE_HIT_ACTIVE;
         set_current_kprobe(p, regs);
         return 1;
 no_kprobe:
-        preempt_enable_no_resched();
         return ret;
 }
         /*
          * By returning a non-zero value, we are telling
          * kprobe_handler() that we have handled unlocking
-         * and re-enabling preemption.
+         * and re-enabling preemption
          */
         return 1;
 }
                                        unsigned long val, void *data)
 {
         struct die_args *args = (struct die_args *)data;
+        int ret = NOTIFY_DONE;
+        preempt_disable();
         switch (val) {
         case DIE_INT3:
                 if (kprobe_handler(args->regs))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         case DIE_DEBUG:
                 if (post_kprobe_handler(args->regs))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         case DIE_GPF:
-                if (kprobe_running() &&
-                    kprobe_fault_handler(args->regs, args->trapnr))
-                        return NOTIFY_STOP;
-                break;
         case DIE_PAGE_FAULT:
                 if (kprobe_running() &&
                     kprobe_fault_handler(args->regs, args->trapnr))
-                        return NOTIFY_STOP;
+                        ret = NOTIFY_STOP;
                 break;
         default:
                 break;
         }
-        return NOTIFY_DONE;
+        preempt_enable();
+        return ret;
 }
 int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
 void __kprobes jprobe_return(void)
 {
-        preempt_enable_no_resched();
         asm volatile ("       xchg   %%rbx,%%rsp     \n"
                       "       int3                      \n"
                       "       .globl jprobe_return_end  \n"

1da177e4c3f4

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/* * linux/fs/fat/dir.c * * directory handling functions for fat-based filesystems * * Written 1992,1993 by Werner Almesberger * * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu> * * VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu> * Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk> * Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de> */ #include <linux/module.h> #include <linux/slab.h> #include <linux/time.h> #include <linux/smp_lock.h> #include <linux/buffer_head.h> #include <linux/compat.h> #include <asm/uaccess.h> #include "fat.h" static inline loff_t fat_make_i_pos(struct super_block *sb, struct buffer_head *bh, struct msdos_dir_entry *de) { return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits) | (de - (struct msdos_dir_entry *)bh->b_data); } static inline void fat_dir_readahead(struct inode *dir, sector_t iblock, sector_t phys) { struct super_block *sb = dir->i_sb; struct msdos_sb_info *sbi = MSDOS_SB(sb); struct buffer_head *bh; int sec; /* This is not a first sector of cluster, or sec_per_clus == 1 */ if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1) return; /* root dir of FAT12/FAT16 */ if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO)) return; bh = sb_find_get_block(sb, phys); if (bh == NULL || !buffer_uptodate(bh)) { for (sec = 0; sec < sbi->sec_per_clus; sec++) sb_breadahead(sb, phys + sec); } brelse(bh); } /* Returns the inode number of the directory entry at offset pos. If bh is non-NULL, it is brelse'd before. Pos is incremented. The buffer header is returned in bh. AV. Most often we do it item-by-item. Makes sense to optimize. AV. OK, there we go: if both bh and de are non-NULL we assume that we just AV. want the next entry (took one explicit de=NULL in vfat/namei.c). AV. It's done in fat_get_entry() (inlined), here the slow case lives. AV. Additionally, when we return -1 (i.e. reached the end of directory) AV. we make bh NULL. */ static int fat__get_entry(struct inode *dir, loff_t *pos, struct buffer_head **bh, struct msdos_dir_entry **de) { struct super_block *sb = dir->i_sb; sector_t phys, iblock; unsigned long mapped_blocks; int err, offset; next: if (*bh) brelse(*bh); *bh = NULL; iblock = *pos >> sb->s_blocksize_bits; err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0); if (err || !phys) return -1; /* beyond EOF or error */ fat_dir_readahead(dir, iblock, phys); *bh = sb_bread(sb, phys); if (*bh == NULL) { printk(KERN_ERR "FAT: Directory bread(block %llu) failed\n", (llu)phys); /* skip this block */ *pos = (iblock + 1) << sb->s_blocksize_bits; goto next; } offset = *pos & (sb->s_blocksize - 1); *pos += sizeof(struct msdos_dir_entry); *de = (struct msdos_dir_entry *)((*bh)->b_data + offset); return 0; } static inline int fat_get_entry(struct inode *dir, loff_t *pos, struct buffer_head **bh, struct msdos_dir_entry **de) { /* Fast stuff first */ if (*bh && *de && (*de - (struct msdos_dir_entry *)(*bh)->b_data) < MSDOS_SB(dir->i_sb)->dir_per_block - 1) { *pos += sizeof(struct msdos_dir_entry); (*de)++; return 0; } return fat__get_entry(dir, pos, bh, de); } /* * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII. * If uni_xlate is enabled and we can't get a 1:1 conversion, use a * colon as an escape character since it is normally invalid on the vfat * filesystem. The following four characters are the hexadecimal digits * of Unicode value. This lets us do a full dump and restore of Unicode * filenames. We could get into some trouble with long Unicode names, * but ignore that right now. * Ahem... Stack smashing in ring 0 isn't fun. Fixed. */ static int uni16_to_x8(unsigned char *ascii, const wchar_t *uni, int len, int uni_xlate, struct nls_table *nls) { const wchar_t *ip; wchar_t ec; unsigned char *op, nc; int charlen; int k; ip = uni; op = ascii; while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) { ec = *ip++; if ( (charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) { op += charlen; len -= charlen; } else { if (uni_xlate == 1) { *op = ':'; for (k = 4; k > 0; k--) { nc = ec & 0xF; op[k] = nc > 9 ? nc + ('a' - 10) : nc + '0'; ec >>= 4; } op += 5; len -= 5; } else { *op++ = '?'; len--; } } } if (unlikely(*ip)) { printk(KERN_WARNING "FAT: filename was truncated while " "converting."); } *op = 0; return (op - ascii); } static inline int fat_uni_to_x8(struct msdos_sb_info *sbi, const wchar_t *uni, unsigned char *buf, int size) { if (sbi->options.utf8) return utf8_wcstombs(buf, uni, size); else return uni16_to_x8(buf, uni, size, sbi->options.unicode_xlate, sbi->nls_io); } static inline int fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni) { int charlen; charlen = t->char2uni(c, clen, uni); if (charlen < 0) { *uni = 0x003f; /* a question mark */ charlen = 1; } return charlen; } static inline int fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni) { int charlen; wchar_t wc; charlen = t->char2uni(c, clen, &wc); if (charlen < 0) { *uni = 0x003f; /* a question mark */ charlen = 1; } else if (charlen <= 1) { unsigned char nc = t->charset2lower[*c]; if (!nc) nc = *c; if ( (charlen = t->char2uni(&nc, 1, uni)) < 0) { *uni = 0x003f; /* a question mark */ charlen = 1; } } else *uni = wc; return charlen; } static inline int fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size, wchar_t *uni_buf, unsigned short opt, int lower) { int len = 0; if (opt & VFAT_SFN_DISPLAY_LOWER) len = fat_short2lower_uni(nls, buf, buf_size, uni_buf); else if (opt & VFAT_SFN_DISPLAY_WIN95) len = fat_short2uni(nls, buf, buf_size, uni_buf); else if (opt & VFAT_SFN_DISPLAY_WINNT) { if (lower) len = fat_short2lower_uni(nls, buf, buf_size, uni_buf); else len = fat_short2uni(nls, buf, buf_size, uni_buf); } else len = fat_short2uni(nls, buf, buf_size, uni_buf); return len; } static inline int fat_name_match(struct msdos_sb_info *sbi, const unsigned char *a, int a_len, const unsigned char *b, int b_len) { if (a_len != b_len) return 0; if (sbi->options.name_check != 's') return !nls_strnicmp(sbi->nls_io, a, b, a_len); else return !memcmp(a, b, a_len); } enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, }; /** * fat_parse_long - Parse extended directory entry. * * This function returns zero on success, negative value on error, or one of * the following: * * %PARSE_INVALID - Directory entry is invalid. * %PARSE_NOT_LONGNAME - Directory entry does not contain longname. * %PARSE_EOF - Directory has no more entries. */ static int fat_parse_long(struct inode *dir, loff_t *pos, struct buffer_head **bh, struct msdos_dir_entry **de, wchar_t **unicode, unsigned char *nr_slots) { struct msdos_dir_slot *ds; unsigned char id, slot, slots, alias_checksum; if (!*unicode) { *unicode = __getname(); if (!*unicode) { brelse(*bh); return -ENOMEM; } } parse_long: slots = 0; ds = (struct msdos_dir_slot *)*de; id = ds->id; if (!(id & 0x40)) return PARSE_INVALID; slots = id & ~0x40; if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */ return PARSE_INVALID; *nr_slots = slots; alias_checksum = ds->alias_checksum; slot = slots; while (1) { int offset; slot--; offset = slot * 13; fat16_towchar(*unicode + offset, ds->name0_4, 5); fat16_towchar(*unicode + offset + 5, ds->name5_10, 6); fat16_towchar(*unicode + offset + 11, ds->name11_12, 2); if (ds->id & 0x40) (*unicode)[offset + 13] = 0; if (fat_get_entry(dir, pos, bh, de) < 0) return PARSE_EOF; if (slot == 0) break; ds = (struct msdos_dir_slot *)*de; if (ds->attr != ATTR_EXT) return PARSE_NOT_LONGNAME; if ((ds->id & ~0x40) != slot) goto parse_long; if (ds->alias_checksum != alias_checksum) goto parse_long; } if ((*de)->name[0] == DELETED_FLAG) return PARSE_INVALID; if ((*de)->attr == ATTR_EXT) goto parse_long; if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME)) return PARSE_INVALID; if (fat_checksum((*de)->name) != alias_checksum) *nr_slots = 0; return 0; } /* * Maximum buffer size of short name. * [(MSDOS_NAME + '.') * max one char + nul] * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul] */ #define FAT_MAX_SHORT_SIZE ((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1) /* * Maximum buffer size of unicode chars from slots. * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)] */ #define FAT_MAX_UNI_CHARS ((MSDOS_SLOTS - 1) * 13 + 1) #define FAT_MAX_UNI_SIZE (FAT_MAX_UNI_CHARS * sizeof(wchar_t)) /* * Return values: negative -> error, 0 -> not found, positive -> found, * value is the total amount of slots, including the shortname entry. */ int fat_search_long(struct inode *inode, const unsigned char *name, int name_len, struct fat_slot_info *sinfo) { struct super_block *sb = inode->i_sb; struct msdos_sb_info *sbi = MSDOS_SB(sb); struct buffer_head *bh = NULL; struct msdos_dir_entry *de; struct nls_table *nls_disk = sbi->nls_disk; unsigned char nr_slots; wchar_t bufuname[14]; wchar_t *unicode = NULL; unsigned char work[MSDOS_NAME]; unsigned char bufname[FAT_MAX_SHORT_SIZE]; unsigned short opt_shortname = sbi->options.shortname; loff_t cpos = 0; int chl, i, j, last_u, err, len; err = -ENOENT; while (1) { if (fat_get_entry(inode, &cpos, &bh, &de) == -1) goto end_of_dir; parse_record: nr_slots = 0; if (de->name[0] == DELETED_FLAG) continue; if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME)) continue; if (de->attr != ATTR_EXT && IS_FREE(de->name)) continue; if (de->attr == ATTR_EXT) { int status = fat_parse_long(inode, &cpos, &bh, &de, &unicode, &nr_slots); if (status < 0) { err = status; goto end_of_dir; } else if (status == PARSE_INVALID) continue; else if (status == PARSE_NOT_LONGNAME) goto parse_record; else if (status == PARSE_EOF) goto end_of_dir; } memcpy(work, de->name, sizeof(de->name)); /* see namei.c, msdos_format_name */ if (work[0] == 0x05) work[0] = 0xE5; for (i = 0, j = 0, last_u = 0; i < 8;) { if (!work[i]) break; chl = fat_shortname2uni(nls_disk, &work[i], 8 - i, &bufuname[j++], opt_shortname, de->lcase & CASE_LOWER_BASE); if (chl <= 1) { if (work[i] != ' ') last_u = j; } else { last_u = j; } i += chl; } j = last_u; fat_short2uni(nls_disk, ".", 1, &bufuname[j++]); for (i = 8; i < MSDOS_NAME;) { if (!work[i]) break; chl = fat_shortname2uni(nls_disk, &work[i], MSDOS_NAME - i, &bufuname[j++], opt_shortname, de->lcase & CASE_LOWER_EXT); if (chl <= 1) { if (work[i] != ' ') last_u = j; } else { last_u = j; } i += chl; } if (!last_u) continue; /* Compare shortname */ bufuname[last_u] = 0x0000; len = fat_uni_to_x8(sbi, bufuname, bufname, sizeof(bufname)); if (fat_name_match(sbi, name, name_len, bufname, len)) goto found; if (nr_slots) { void *longname = unicode + FAT_MAX_UNI_CHARS; int size = PATH_MAX - FAT_MAX_UNI_SIZE; /* Compare longname */ len = fat_uni_to_x8(sbi, unicode, longname, size); if (fat_name_match(sbi, name, name_len, longname, len)) goto found; } } found: nr_slots++; /* include the de */ sinfo->slot_off = cpos - nr_slots * sizeof(*de); sinfo->nr_slots = nr_slots; sinfo->de = de; sinfo->bh = bh; sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); err = 0; end_of_dir: if (unicode) __putname(unicode); return err; } EXPORT_SYMBOL_GPL(fat_search_long); struct fat_ioctl_filldir_callback { void __user *dirent; int result; /* for dir ioctl */ const char *longname; int long_len; const char *shortname; int short_len; }; static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent, filldir_t filldir, int short_only, int both) { struct super_block *sb = inode->i_sb; struct msdos_sb_info *sbi = MSDOS_SB(sb); struct buffer_head *bh; struct msdos_dir_entry *de; struct nls_table *nls_disk = sbi->nls_disk; unsigned char nr_slots; wchar_t bufuname[14]; wchar_t *unicode = NULL; unsigned char c, work[MSDOS_NAME]; unsigned char bufname[FAT_MAX_SHORT_SIZE], *ptname = bufname; unsigned short opt_shortname = sbi->options.shortname; int isvfat = sbi->options.isvfat; int nocase = sbi->options.nocase; const char *fill_name = NULL; unsigned long inum; unsigned long lpos, dummy, *furrfu = &lpos; loff_t cpos; int chi, chl, i, i2, j, last, last_u, dotoffset = 0, fill_len = 0; int ret = 0; lock_super(sb); cpos = filp->f_pos; /* Fake . and .. for the root directory. */ if (inode->i_ino == MSDOS_ROOT_INO) { while (cpos < 2) { if (filldir(dirent, "..", cpos+1, cpos, MSDOS_ROOT_INO, DT_DIR) < 0) goto out; cpos++; filp->f_pos++; } if (cpos == 2) { dummy = 2; furrfu = &dummy; cpos = 0; } } if (cpos & (sizeof(struct msdos_dir_entry) - 1)) { ret = -ENOENT; goto out; } bh = NULL; get_new: if (fat_get_entry(inode, &cpos, &bh, &de) == -1) goto end_of_dir; parse_record: nr_slots = 0; /* * Check for long filename entry, but if short_only, we don't * need to parse long filename. */ if (isvfat && !short_only) { if (de->name[0] == DELETED_FLAG) goto record_end; if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME)) goto record_end; if (de->attr != ATTR_EXT && IS_FREE(de->name)) goto record_end; } else { if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name)) goto record_end; } if (isvfat && de->attr == ATTR_EXT) { int status = fat_parse_long(inode, &cpos, &bh, &de, &unicode, &nr_slots); if (status < 0) { filp->f_pos = cpos; ret = status; goto out; } else if (status == PARSE_INVALID) goto record_end; else if (status == PARSE_NOT_LONGNAME) goto parse_record; else if (status == PARSE_EOF) goto end_of_dir; if (nr_slots) { void *longname = unicode + FAT_MAX_UNI_CHARS; int size = PATH_MAX - FAT_MAX_UNI_SIZE; int len = fat_uni_to_x8(sbi, unicode, longname, size); fill_name = longname; fill_len = len; /* !both && !short_only, so we don't need shortname. */ if (!both) goto start_filldir; } } if (sbi->options.dotsOK) { ptname = bufname; dotoffset = 0; if (de->attr & ATTR_HIDDEN) { *ptname++ = '.'; dotoffset = 1; } } memcpy(work, de->name, sizeof(de->name)); /* see namei.c, msdos_format_name */ if (work[0] == 0x05) work[0] = 0xE5; for (i = 0, j = 0, last = 0, last_u = 0; i < 8;) { if (!(c = work[i])) break; chl = fat_shortname2uni(nls_disk, &work[i], 8 - i, &bufuname[j++], opt_shortname, de->lcase & CASE_LOWER_BASE); if (chl <= 1) { ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c; if (c != ' ') { last = i; last_u = j; } } else { last_u = j; for (chi = 0; chi < chl && i < 8; chi++) { ptname[i] = work[i]; i++; last = i; } } } i = last; j = last_u; fat_short2uni(nls_disk, ".", 1, &bufuname[j++]); ptname[i++] = '.'; for (i2 = 8; i2 < MSDOS_NAME;) { if (!(c = work[i2])) break; chl = fat_shortname2uni(nls_disk, &work[i2], MSDOS_NAME - i2, &bufuname[j++], opt_shortname, de->lcase & CASE_LOWER_EXT); if (chl <= 1) { i2++; ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c; if (c != ' ') { last = i; last_u = j; } } else { last_u = j; for (chi = 0; chi < chl && i2 < MSDOS_NAME; chi++) { ptname[i++] = work[i2++]; last = i; } } } if (!last) goto record_end; i = last + dotoffset; j = last_u; if (isvfat) { bufuname[j] = 0x0000; i = fat_uni_to_x8(sbi, bufuname, bufname, sizeof(bufname)); } if (nr_slots) { /* hack for fat_ioctl_filldir() */ struct fat_ioctl_filldir_callback *p = dirent; p->longname = fill_name; p->long_len = fill_len; p->shortname = bufname; p->short_len = i; fill_name = NULL; fill_len = 0; } else { fill_name = bufname; fill_len = i; } start_filldir: lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry); if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) inum = inode->i_ino; else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) { inum = parent_ino(filp->f_path.dentry); } else { loff_t i_pos = fat_make_i_pos(sb, bh, de); struct inode *tmp = fat_iget(sb, i_pos); if (tmp) { inum = tmp->i_ino; iput(tmp); } else inum = iunique(sb, MSDOS_ROOT_INO); } if (filldir(dirent, fill_name, fill_len, *furrfu, inum, (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0) goto fill_failed; record_end: furrfu = &lpos; filp->f_pos = cpos; goto get_new; end_of_dir: filp->f_pos = cpos; fill_failed: brelse(bh); if (unicode) __putname(unicode); out: unlock_super(sb); return ret; } static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir) { struct inode *inode = filp->f_path.dentry->d_inode; return __fat_readdir(inode, filp, dirent, filldir, 0, 0); } #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type) \ static int func(void *__buf, const char *name, int name_len, \ loff_t offset, u64 ino, unsigned int d_type) \ { \ struct fat_ioctl_filldir_callback *buf = __buf; \ struct dirent_type __user *d1 = buf->dirent; \ struct dirent_type __user *d2 = d1 + 1; \ \ if (buf->result) \ return -EINVAL; \ buf->result++; \ \ if (name != NULL) { \ /* dirent has only short name */ \ if (name_len >= sizeof(d1->d_name)) \ name_len = sizeof(d1->d_name) - 1; \ \ if (put_user(0, d2->d_name) || \ put_user(0, &d2->d_reclen) || \ copy_to_user(d1->d_name, name, name_len) || \ put_user(0, d1->d_name + name_len) || \ put_user(name_len, &d1->d_reclen)) \ goto efault; \ } else { \ /* dirent has short and long name */ \ const char *longname = buf->longname; \ int long_len = buf->long_len; \ const char *shortname = buf->shortname; \ int short_len = buf->short_len; \ \ if (long_len >= sizeof(d1->d_name)) \ long_len = sizeof(d1->d_name) - 1; \ if (short_len >= sizeof(d1->d_name)) \ short_len = sizeof(d1->d_name) - 1; \ \ if (copy_to_user(d2->d_name, longname, long_len) || \ put_user(0, d2->d_name + long_len) || \ put_user(long_len, &d2->d_reclen) || \ put_user(ino, &d2->d_ino) || \ put_user(offset, &d2->d_off) || \ copy_to_user(d1->d_name, shortname, short_len) || \ put_user(0, d1->d_name + short_len) || \ put_user(short_len, &d1->d_reclen)) \ goto efault; \ } \ return 0; \ efault: \ buf->result = -EFAULT; \ return -EFAULT; \ } FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent) static int fat_ioctl_readdir(struct inode *inode, struct file *filp, void __user *dirent, filldir_t filldir, int short_only, int both) { struct fat_ioctl_filldir_callback buf; int ret; buf.dirent = dirent; buf.result = 0; mutex_lock(&inode->i_mutex); ret = -ENOENT; if (!IS_DEADDIR(inode)) { ret = __fat_readdir(inode, filp, &buf, filldir, short_only, both); } mutex_unlock(&inode->i_mutex); if (ret >= 0) ret = buf.result; return ret; } static int fat_dir_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) { struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg; int short_only, both; switch (cmd) { case VFAT_IOCTL_READDIR_SHORT: short_only = 1; both = 0; break; case VFAT_IOCTL_READDIR_BOTH: short_only = 0; both = 1; break; default: return fat_generic_ioctl(inode, filp, cmd, arg); } if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2]))) return -EFAULT; /* * Yes, we don't need this put_user() absolutely. However old * code didn't return the right value. So, app use this value, * in order to check whether it is EOF. */ if (put_user(0, &d1->d_reclen)) return -EFAULT; return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir, short_only, both); } #ifdef CONFIG_COMPAT #define VFAT_IOCTL_READDIR_BOTH32 _IOR('r', 1, struct compat_dirent[2]) #define VFAT_IOCTL_READDIR_SHORT32 _IOR('r', 2, struct compat_dirent[2]) FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent) static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd, unsigned long arg) { struct inode *inode = filp->f_path.dentry->d_inode; struct compat_dirent __user *d1 = compat_ptr(arg); int short_only, both; switch (cmd) { case VFAT_IOCTL_READDIR_SHORT32: short_only = 1; both = 0; break; case VFAT_IOCTL_READDIR_BOTH32: short_only = 0; both = 1; break; default: return -ENOIOCTLCMD; } if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2]))) return -EFAULT; /* * Yes, we don't need this put_user() absolutely. However old * code didn't return the right value. So, app use this value, * in order to check whether it is EOF. */ if (put_user(0, &d1->d_reclen)) return -EFAULT; return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir, short_only, both); } #endif /* CONFIG_COMPAT */ const struct file_operations fat_dir_operations = { .llseek = generic_file_llseek, .read = generic_read_dir, .readdir = fat_readdir, .ioctl = fat_dir_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = fat_compat_dir_ioctl, #endif .fsync = file_fsync, }; static int fat_get_short_entry(struct inode *dir, loff_t *pos, struct buffer_head **bh, struct msdos_dir_entry **de) { while (fat_get_entry(dir, pos, bh, de) >= 0) { /* free entry or long name entry or volume label */ if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME)) return 0; } return -ENOENT; } /* * The ".." entry can not provide the "struct fat_slot_info" informations * for inode. So, this function provide the some informations only. */ int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh, struct msdos_dir_entry **de, loff_t *i_pos) { loff_t offset; offset = 0; *bh = NULL; while (fat_get_short_entry(dir, &offset, bh, de) >= 0) { if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME)) { *i_pos = fat_make_i_pos(dir->i_sb, *bh, *de); return 0; } } return -ENOENT; } EXPORT_SYMBOL_GPL(fat_get_dotdot_entry); /* See if directory is empty */ int fat_dir_empty(struct inode *dir) { struct buffer_head *bh; struct msdos_dir_entry *de; loff_t cpos; int result = 0; bh = NULL; cpos = 0; while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) { if (strncmp(de->name, MSDOS_DOT , MSDOS_NAME) && strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) { result = -ENOTEMPTY; break; } } brelse(bh); return result; } EXPORT_SYMBOL_GPL(fat_dir_empty); /* * fat_subdirs counts the number of sub-directories of dir. It can be run * on directories being created. */ int fat_subdirs(struct inode *dir) { struct buffer_head *bh; struct msdos_dir_entry *de; loff_t cpos; int count = 0; bh = NULL; cpos = 0; while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) { if (de->attr & ATTR_DIR) count++; } brelse(bh); return count; } /* * Scans a directory for a given file (name points to its formatted name). * Returns an error code or zero. */ int fat_scan(struct inode *dir, const unsigned char *name, struct fat_slot_info *sinfo) { struct super_block *sb = dir->i_sb; sinfo->slot_off = 0; sinfo->bh = NULL; while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh, &sinfo->de) >= 0) { if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) { sinfo->slot_off -= sizeof(*sinfo->de); sinfo->nr_slots = 1; sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); return 0; } } return -ENOENT; } EXPORT_SYMBOL_GPL(fat_scan); static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots) { struct super_block *sb = dir->i_sb; struct buffer_head *bh; struct msdos_dir_entry *de, *endp; int err = 0, orig_slots; while (nr_slots) { bh = NULL; if (fat_get_entry(dir, &pos, &bh, &de) < 0) { err = -EIO; break; } orig_slots = nr_slots; endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize); while (nr_slots && de < endp) { de->name[0] = DELETED_FLAG; de++; nr_slots--; } mark_buffer_dirty(bh); if (IS_DIRSYNC(dir)) err = sync_dirty_buffer(bh); brelse(bh); if (err) break; /* pos is *next* de's position, so this does `- sizeof(de)' */ pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de); } return err; } int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo) { struct msdos_dir_entry *de; struct buffer_head *bh; int err = 0, nr_slots; /* * First stage: Remove the shortname. By this, the directory * entry is removed. */ nr_slots = sinfo->nr_slots; de = sinfo->de; sinfo->de = NULL; bh = sinfo->bh; sinfo->bh = NULL; while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) { de->name[0] = DELETED_FLAG; de--; nr_slots--; } mark_buffer_dirty(bh); if (IS_DIRSYNC(dir)) err = sync_dirty_buffer(bh); brelse(bh); if (err) return err; dir->i_version++; if (nr_slots) { /* * Second stage: remove the remaining longname slots. * (This directory entry is already removed, and so return * the success) */ err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots); if (err) { printk(KERN_WARNING "FAT: Couldn't remove the long name slots\n"); } } dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC; if (IS_DIRSYNC(dir)) (void)fat_sync_inode(dir); else mark_inode_dirty(dir); return 0; } EXPORT_SYMBOL_GPL(fat_remove_entries); static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used, struct buffer_head **bhs, int nr_bhs) { struct super_block *sb = dir->i_sb; sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus; int err, i, n; /* Zeroing the unused blocks on this cluster */ blknr += nr_used; n = nr_used; while (blknr < last_blknr) { bhs[n] = sb_getblk(sb, blknr); if (!bhs[n]) { err = -ENOMEM; goto error; } memset(bhs[n]->b_data, 0, sb->s_blocksize); set_buffer_uptodate(bhs[n]); mark_buffer_dirty(bhs[n]); n++; blknr++; if (n == nr_bhs) { if (IS_DIRSYNC(dir)) { err = fat_sync_bhs(bhs, n); if (err) goto error; } for (i = 0; i < n; i++) brelse(bhs[i]); n = 0; } } if (IS_DIRSYNC(dir)) { err = fat_sync_bhs(bhs, n); if (err) goto error; } for (i = 0; i < n; i++) brelse(bhs[i]); return 0; error: for (i = 0; i < n; i++) bforget(bhs[i]); return err; } int fat_alloc_new_dir(struct inode *dir, struct timespec *ts) { struct super_block *sb = dir->i_sb; struct msdos_sb_info *sbi = MSDOS_SB(sb); struct buffer_head *bhs[MAX_BUF_PER_PAGE]; struct msdos_dir_entry *de; sector_t blknr; __le16 date, time; u8 time_cs; int err, cluster; err = fat_alloc_clusters(dir, &cluster, 1); if (err) goto error; blknr = fat_clus_to_blknr(sbi, cluster); bhs[0] = sb_getblk(sb, blknr); if (!bhs[0]) { err = -ENOMEM; goto error_free; } fat_time_unix2fat(sbi, ts, &time, &date, &time_cs); de = (struct msdos_dir_entry *)bhs[0]->b_data; /* filling the new directory slots ("." and ".." entries) */ memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME); memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME); de->attr = de[1].attr = ATTR_DIR; de[0].lcase = de[1].lcase = 0; de[0].time = de[1].time = time; de[0].date = de[1].date = date; if (sbi->options.isvfat) { /* extra timestamps */ de[0].ctime = de[1].ctime = time; de[0].ctime_cs = de[1].ctime_cs = time_cs; de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date; } else { de[0].ctime = de[1].ctime = 0; de[0].ctime_cs = de[1].ctime_cs = 0; de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0; } de[0].start = cpu_to_le16(cluster); de[0].starthi = cpu_to_le16(cluster >> 16); de[1].start = cpu_to_le16(MSDOS_I(dir)->i_logstart); de[1].starthi = cpu_to_le16(MSDOS_I(dir)->i_logstart >> 16); de[0].size = de[1].size = 0; memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de)); set_buffer_uptodate(bhs[0]); mark_buffer_dirty(bhs[0]); err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE); if (err) goto error_free; return cluster; error_free: fat_free_clusters(dir, cluster); error: return err; } EXPORT_SYMBOL_GPL(fat_alloc_new_dir); static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots, int *nr_cluster, struct msdos_dir_entry **de, struct buffer_head **bh, loff_t *i_pos) { struct super_block *sb = dir->i_sb; struct msdos_sb_info *sbi = MSDOS_SB(sb); struct buffer_head *bhs[MAX_BUF_PER_PAGE]; sector_t blknr, start_blknr, last_blknr; unsigned long size, copy; int err, i, n, offset, cluster[2]; /* * The minimum cluster size is 512bytes, and maximum entry * size is 32*slots (672bytes). So, iff the cluster size is * 512bytes, we may need two clusters. */ size = nr_slots * sizeof(struct msdos_dir_entry); *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits; BUG_ON(*nr_cluster > 2); err = fat_alloc_clusters(dir, cluster, *nr_cluster); if (err) goto error; /* * First stage: Fill the directory entry. NOTE: This cluster * is not referenced from any inode yet, so updates order is * not important. */ i = n = copy = 0; do { start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]); last_blknr = start_blknr + sbi->sec_per_clus; while (blknr < last_blknr) { bhs[n] = sb_getblk(sb, blknr); if (!bhs[n]) { err = -ENOMEM; goto error_nomem; } /* fill the directory entry */ copy = min(size, sb->s_blocksize); memcpy(bhs[n]->b_data, slots, copy); slots += copy; size -= copy; set_buffer_uptodate(bhs[n]); mark_buffer_dirty(bhs[n]); if (!size) break; n++; blknr++; } } while (++i < *nr_cluster); memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy); offset = copy - sizeof(struct msdos_dir_entry); get_bh(bhs[n]); *bh = bhs[n]; *de = (struct msdos_dir_entry *)((*bh)->b_data + offset); *i_pos = fat_make_i_pos(sb, *bh, *de); /* Second stage: clear the rest of cluster, and write outs */ err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE); if (err) goto error_free; return cluster[0]; error_free: brelse(*bh); *bh = NULL; n = 0; error_nomem: for (i = 0; i < n; i++) bforget(bhs[i]); fat_free_clusters(dir, cluster[0]); error: return err; } int fat_add_entries(struct inode *dir, void *slots, int nr_slots, struct fat_slot_info *sinfo) { struct super_block *sb = dir->i_sb; struct msdos_sb_info *sbi = MSDOS_SB(sb); struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */ struct msdos_dir_entry *de; int err, free_slots, i, nr_bhs; loff_t pos, i_pos; sinfo->nr_slots = nr_slots; /* First stage: search free direcotry entries */ free_slots = nr_bhs = 0; bh = prev = NULL; pos = 0; err = -ENOSPC; while (fat_get_entry(dir, &pos, &bh, &de) > -1) { /* check the maximum size of directory */ if (pos >= FAT_MAX_DIR_SIZE) goto error; if (IS_FREE(de->name)) { if (prev != bh) { get_bh(bh); bhs[nr_bhs] = prev = bh; nr_bhs++; } free_slots++; if (free_slots == nr_slots) goto found; } else { for (i = 0; i < nr_bhs; i++) brelse(bhs[i]); prev = NULL; free_slots = nr_bhs = 0; } } if (dir->i_ino == MSDOS_ROOT_INO) { if (sbi->fat_bits != 32) goto error; } else if (MSDOS_I(dir)->i_start == 0) { printk(KERN_ERR "FAT: Corrupted directory (i_pos %lld)\n", MSDOS_I(dir)->i_pos); err = -EIO; goto error; } found: err = 0; pos -= free_slots * sizeof(*de); nr_slots -= free_slots; if (free_slots) { /* * Second stage: filling the free entries with new entries. * NOTE: If this slots has shortname, first, we write * the long name slots, then write the short name. */ int size = free_slots * sizeof(*de); int offset = pos & (sb->s_blocksize - 1); int long_bhs = nr_bhs - (nr_slots == 0); /* Fill the long name slots. */ for (i = 0; i < long_bhs; i++) { int copy = min_t(int, sb->s_blocksize - offset, size); memcpy(bhs[i]->b_data + offset, slots, copy); mark_buffer_dirty(bhs[i]); offset = 0; slots += copy; size -= copy; } if (long_bhs && IS_DIRSYNC(dir)) err = fat_sync_bhs(bhs, long_bhs); if (!err && i < nr_bhs) { /* Fill the short name slot. */ int copy = min_t(int, sb->s_blocksize - offset, size); memcpy(bhs[i]->b_data + offset, slots, copy); mark_buffer_dirty(bhs[i]); if (IS_DIRSYNC(dir)) err = sync_dirty_buffer(bhs[i]); } for (i = 0; i < nr_bhs; i++) brelse(bhs[i]); if (err) goto error_remove; } if (nr_slots) { int cluster, nr_cluster; /* * Third stage: allocate the cluster for new entries. * And initialize the cluster with new entries, then * add the cluster to dir. */ cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster, &de, &bh, &i_pos); if (cluster < 0) { err = cluster; goto error_remove; } err = fat_chain_add(dir, cluster, nr_cluster); if (err) { fat_free_clusters(dir, cluster); goto error_remove; } if (dir->i_size & (sbi->cluster_size - 1)) { fat_fs_panic(sb, "Odd directory size"); dir->i_size = (dir->i_size + sbi->cluster_size - 1) & ~((loff_t)sbi->cluster_size - 1); } dir->i_size += nr_cluster << sbi->cluster_bits; MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits; } sinfo->slot_off = pos; sinfo->de = de; sinfo->bh = bh; sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); return 0; error: brelse(bh); for (i = 0; i < nr_bhs; i++) brelse(bhs[i]); return err; error_remove: brelse(bh); if (free_slots) __fat_remove_entries(dir, pos, free_slots); return err; } EXPORT_SYMBOL_GPL(fat_add_entries);


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